The present invention relates to a semiconductor device and a method for manufacturing the same.
In order to control a large current flowing in a load, a semiconductor power device such as a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is used. If there is reverse coupling of power supply in the use of such a semiconductor power device, the parasitic diode formed between the source and drain of the power MOSFET is forward-biased. As a result, unintendedly the load might be continuously energized, resulting in destruction of the load or thermal destruction of the power MOSFET. One technique to prevent continuous energization of the load is that a diode or the like is series-coupled between the semiconductor power device and the power supply.
For example, Japanese Unexamined Patent Application Publication No. 2013-38908 discloses a technique that a semiconductor element for protection against power supply reverse coupling is provided on the upstream (power supply side) of a semiconductor element for energization control in order to achieve protection against battery reverse coupling.